The application relates to an internal combustion engine and a method for operation thereof. An exemplary embodiment of the method involves providing a crank casing pressure sensor in an internal combustion engine, measuring a crank casing pressure using the crank casing pressure sensor, evaluating the crank casing pressure measurements, and controlling the internal combustion engine, a component thereof, or a device attached to the internal combustion engine using crank casing pressure measurements. An exemplary embodiment of the internal combustion engine has a crank casing having the crank casing pressure, a combustion chamber bounded on one side and around a circumference by a cylinder and bounded on the other side by a reciprocating piston, a crankshaft driven by the reciprocating piston which is rotatably mounted in the crank casing, an inlet opening in the crank casing which allows combustion air to enter into the crank casing, an outlet opening out of the combustion chamber, one or more overflow ducts connecting the crank casing to the combustion chamber in the region of the bottom dead center of the piston, and a sensor to detect the rotational position of the crankshaft.
In internal combustion engines, for example in two-stroke engines, a pressure sensor in the crank casing may, during operation, supply data used to control the internal combustion engine, for example to control the fed-in quantity of fuel, to control the injection time, or to control the ignition time. DE 10 2008 019 088 A1 presents an internal combustion engine. Therein, the pressure sensor in the crank casing is used to determine at what times the metering valve, which feeds the fuel into the crank casing, is opened and closed.
U.S. Pat. No. 7,536,983 B2 discloses a two-stroke engine having a pressure sensor which determines the crank casing pressure. The crank casing pressure is used during operation therein to determine the air mass flow through the combustion chamber, and to determine therefrom the quantity of fuel to be fed in.
Internal combustion engines, for example internal combustion engines in hand-guided tools, may be used at different altitudes. Differences in altitude result in changes in the ambient pressure. The different pressure level of the ambient pressure has to be taken into account in the actuation of the internal combustion engine, in particular in the determination of the quantity of fuel which is to be fed in. In many devices this is done by means of corresponding adjustment screws on a carburetor of the internal combustion engine, which are to be adjusted by the user.